Pin keyboard improvements.

chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js

Index: chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js
diff --git a/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js b/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js
index d6c28711b4d28f8981da2fa4aa487e02dafc6e40..9843ef239cade01bcdf2f38f1928877e5a1667a7 100644
--- a/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js
+++ b/chrome/browser/resources/chromeos/quick_unlock/pin_keyboard.js
@@ -53,6 +53,23 @@ Polymer({
       notify: true,
       value: '',
       observer: 'onPinValueChange_'
+    },
+
+    /**
+     * The intervalID used for the backspace button set/clear interval.
+     */
+    intervalId: {

[jdufault, 2016/08/31 19:28:55]

Can we use this.async?

[sammiequon, 2016/08/31 22:30:32]

Done.

+      type: Number,
+      value: 0
+    }
+
+    /**
+     * When the backspace button is held down, it repeatly clears the last
+     * character of the input value every intervalMs.
+     */
+    intervalMs: {
+      type: Number,
+      value: 150
     }
   },
 
@@ -97,12 +114,34 @@ Polymer({
 
   /**
    * Called when the user wants to erase the last character of the entered
-   *  PIN value.
+   * PIN value.
    */
   onPinClear_: function() {
     this.value = this.value.substring(0, this.value.length - 1);
   },
 
+  /**
+   * Called when the user presses the backspace button. Starts a interval
+   * callback to repeatedly clear the last pin value until the interval is
+   * cleared.
+   * @private
+   */
+  onBackspaceMouseDown_: function() {
+    this.onPinClear_();
+    intervalId = setInterval(function() {

[jdufault, 2016/08/31 19:28:55]

this.intervalId_

[sammiequon, 2016/08/31 22:30:32]

Done.

+      this.onPinClear_();
+    }.bind(this), this.intervalMs);
+  },
+
+  /**
+   * Called when the user unpresses the backspace button. Stops the interval
+   * callback.
+   * @private
+   */
+  onBackspaceMouseUpLeave_: function() {

[jdufault, 2016/08/31 19:28:55]

Does this work for tapping?

[sammiequon, 2016/08/31 22:30:32]

Yes.

+    clearInterval(intervalId);

[jdufault, 2016/08/31 19:28:55]

this.intervalId_

[sammiequon, 2016/08/31 22:30:32]

Done.

+  },
+
   /** Called when a key event is pressed while the input element has focus. */
   onInputKeyDown_: function(event) {
     // Up/down pressed, swallow the event to prevent the input value from
@@ -143,6 +182,11 @@ Polymer({
    * @private
    */
   onKeyPress_: function(event) {
+    // If the active element is the input element, the input element itself will
+    // handle the keypresses, so we do not handle them here.
+    if (this.shadowRoot.activeElement == this.inputElement)
+      return;
+
     var code = event.keyCode;
 
     // Enter pressed.